Does TrueDepth provide better eye tracking than Neural Engine alone?

Hi, we are looking at purchasing some development devices and would like to know if there is a difference in eye tracking performance in devices with a TrueDepth camera (iPad Pro) vs those without (iPad 8th gen).

• Does the TrueDepth camera provide more accurate eye tracking?
• Does the iPad pro use infrared for eye tracking since iOS 14 now supports eye tracking on devices with Neural Engine?
• Are there any benefits to the iPad Pro over an 8th gen in terms of eye tracking or face tracking in general?

Thanks!